Expansion Vessel needs re-charing I believe. Sequence OK?

[ThomasCoady]

Hello everybody.

THis post has been covered on FAQ but I do not understand it. I have read a similar post on this website just now and there are variations of it. Please can someone kindly clarify for me:


My boiler, pressure gauge keeps rising to 3 bar and then dropping to 0 bar after I use it, so I top it up and it does the same again. I believe it to be the expansion vessel as mentioned and looked at this afternoon. I have just read a similar post on this and looked at the FAQ.


I fill it up and this keeps happening, but the boiler does not lock out at all and need resetting.


I believe it is not good to isolate the boiler at the valves underneath the combi.

Is the sequence as follows (please ammend it for me if you may if I have gone wrong anywhere):


Filling loop is disonncted to boiler cannot re-fill on own

Undo cap at expansion vessel and check for water leak, if ok:

Drain water from a radiator on the same floor as the boiler (downstairs in my case)

Wait until the gauge is at 0 pressure

Check air charge at vessel cap with a pencil gauge

Re-charge if low to bout 0.7 bar..?

Check charge is at 0.7 bar and replace plastic cap to vessel

Re-fill system to 1 bar when cold as it should be

Vent rad and re-fill to 1 bar again


Is this it?? Or have I missed something as I'd like to do it first time without a fault!!


Thanks for your help everybody and sorry for disturbing you.

 

[Agile]

That is not the advice I gave.

But you seem to have your own views on what is good to do or not do so I dont think there is much point in me replying?

Or would you like me to just repeat what I said before?

Even if I did that then you would presumably disagree again with what I said.

Tony

 

[MANDATE]

The success to re charging a vessel, which is full or partially full with water is twofold.
Pumping it up to 0.8 bar is one part.
If you have a 10 litre vessel full with water, that 10 litres of water has to be pushed out of the vessel and replaced with 'air'. So where is the excess water to go? The system is full so the options are, either drain 10 litres off before re charging or provide an open vent with little resistance where 10 litres can be pushed out while charging.